IRA FLATOW: For the rest of the hour, a look at lighting. Yeah, Sci Fri’s Charles Bergquist is here to tell us why. Charles.

CHARLES BERGQUIST: Hey, Ira. What kind of lights do you have in your house?

IRA FLATOW: Well, of course, we’ve got the windows and some table lamps, floor lamps, maybe some recessed or track lighting, and of course, your chandelier in the dining room.

CHARLES BERGQUIST: OK. But if you were in a Paleolithic cave about 12,000 years ago or more, you didn’t have that dining room chandelier. You probably had about three options for lighting your cave. First was a fireplace, basically a regular campfire.

IRA FLATOW: Yeah, but that took a lot of light to make heat. We’re not talking LCDs here. And campfires can be smoky. And the one thing about them is that they stay in place, right?

CHARLES BERGQUIST: Right. You’re not carrying the campfire around. So for mobile lighting, you basically had a torch, either a big stick or a bundle of sticks. And then there was the Paleolithic stone lamp. That was basically a flat stone with a hole in the middle. And you put animal grease or fat into that hole and some little twigs to make a wick for it.

IRA FLATOW: I get it. So you had your big, your medium, your little, different fires for different uses.

CHARLES BERGQUIST: Right. And so recently scientists studying Paleolithic art went into the Atxurra cave in northern Spain’s Basque Country. And they brought reproductions of these different kinds of lights to try them out. They figured out that if you were a cave artist, you probably used a torch when you were trekking deep into that cave because a torch was bright. But they make a lot of smoke, so they aren’t good for being in a confined space for a long time if you’re painting something.

IRA FLATOW: And that’s what I was wondering about. How could they make these paintings with a torch? As you say, sometimes they’re deep in a cave in a pretty tight space.

CHARLES BERGQUIST: Yeah, not a place you’d want to hang out in a lot of smoke. So they used a torch to explore the cave. But then they switched to the oil lamp for their work light. That stone oil lamp could burn for a long time without giving off a lot of smoke. But it only puts out about as much light as a candle. So you can imagine a cave artist painting just by the light of a flickering candle.

IRA FLATOW: Yeah, one candle. OK. So why did scientists need to go into a cave to figure this out?

CHARLES BERGQUIST: So they were trying to get really accurate data on the specific properties of each of these kinds of lights in the cave, stuff like how long it lasted, the color properties, how far you could see using that light. They’re using all of that illumination data to make a 3D model of a cave with art, sort of like a high-resolution video game so that you could experience those cave paintings under realistic lighting conditions and maybe get a better sense of what the artists themselves experienced and intended.

I asked Inaki Intxaurbe, a PhD student in the Department of Geology at the University of the Basque Country in Spain, what it was like for him to go into that cave carrying an actual torch.

INAKI INTXAURBE: First thing is that the colors that we appreciate are different. The fire only…means only produced reddish colors. So we are going to see the landscape in yellow colors, in red color. It’s going to be different.

And the second thing is that the walls are going to be moving always because the fire is always moving. So the shades are going to be moving. There are going to be a lot of shadows and the smoke also. The smoke also produce a different sensation, I don’t know. The noise also because the fire is always producing noise, no? This type, the sparks are– these type of things.

When we reach, for example, an area with paintings, the sensations are very magical because we are going to see a horse like they seem to be moving. It’s different to go, for example, to a cave we model artificial torches, it’s different.

CHARLES BERGQUIST: Do we know why they chose such an inconvenient place to make their art? Wouldn’t you do it where the light is better?

INAKI INTXAURBE: This is the main question of our shift. We haven’t got the answers yet. But perhaps I think there could be two reasons, more or less. The first reason is that they wanted to find a place to put their painting and which only could be seen by the ones that they want. So this painting is not going to be seen for another person of another group or something like this.

The second reason is that they didn’t have in their minds a bison, for example, or a horse shape. The caves, a concrete wall is telling them to paint the horse or the bison. So if this wall is located close to the entrance, they are going to find the bison there close to the entrance. But if the wall is located in the deepest part of the cave, they are going to explore the entire cave until they are reaching this wall. And they are going to see there, it’s there, this magic wall. And they are going to paint there.

CHARLES BERGQUIST: You’re listening to Science Friday from WNYC Studios. I’m talking with Inaki Intxaurbe, part of a team who recently studied lighting in Paleolithic caves. Would the artist painting these pictures have been working by himself or herself? Or did he have artist helpers holding lights for him?

INAKI INTXAURBE: Yeah, I think that a lot of people, no because there is not enough space for big groups, no? But it doesn’t seem a work for a single person because it’s very dangerous, and you need different torches. For example, we have seen that employing the Paleolithic lights, they need more than 40 minutes to reach the area with rock art.

So we have seen that employing the torches that we have measured, they need at least two torches: one to enter there and the other one to go, again, to the surface. So I think that two-person minimal, yes, because it’s very dangerous and one need be helping the other one to clean and things like that.

CHARLES BERGQUIST: Right. So today when you or I see this art, we’ve got powerful work lights. We’ve got headlamps. Are we all getting the wrong impression of what this art means and how to experience this art?

INAKI INTXAURBE: Absolutely. We have seen that if you port [bring] a torch, for example, the light of the fire is moving always. So the walls are going to be always moving like in the cinema, more or less. They are going to be different shadows.

They are going to be different colors, different intensities. So perhaps they enter it in the cave holding these type of lightings and these motivate him to paint the animal, for example, because the cracks are moving. The shapes they are moving, you know, so in the cave with the light of the flame.

Currently, we use artificial light that they are fixed. So we didn’t appreciate this type of movement. But currently, we are using also digital methods, like video games, for example, like in motor games. And this allow us to appreciate these type of scenarios.

We model the Paleolithic cave, for example, in a computer. And we place different type of fires, for example, and things like that, so we can see how the wall is moving, how the natural scenes are standing or not, and things like that.

CHARLES BERGQUIST: Well, what do you see people misunderstand about Paleolithic art? What do people get wrong, and you’re just like, ah, no?

INAKI INTXAURBE: People if they think about Paleolithic art, they are going to imagine the animals are very beautiful. Perhaps they are going to be a caveman biting this in the kitchen. But this is not the reality.

These type of paintings usually are in this magic space that we have been talking before. But they were not made to be there for aesthetics reason, no? We call these Paleolithic art. But really we don’t know if it’s art because it’s something more important than that.

CHARLES BERGQUIST: Inaki Intxaurbe is a PhD student in the Department of Geology at the University of the Basque Country in Spain. Thank you so much for taking the time to talk with me today.

INAKI INTXAURBE: You’re welcome.

CHARLES BERGQUIST: For Science Friday, I’m Charles Bergquist.

IRA FLATOW: Nice story, Charles. Thanks for bringing it to us.

CHARLES BERGQUIST: Thanks, Ira. Always good to talk about caves.

IRA FLATOW: And that’s about all the time we have for this hour. Charles Bergquist is our director. Our producers are Christie Taylor and Kathleen Davis. Our intern is Emily Zhang. John Dankosky is our news director. Alexa Lim is our senior producer.

And we bid a teary farewell to Alexa, who has been part of our Sci Fri family for almost a decade. Alexa is a terrific producer and a caring comrade. And she has served as an anchor for our team for many, many years, not to mention the only person who could out-dad my dad jokes. She will be missed. We wish her well.

BJ Leiderman composed our theme music. And if you missed any part of the program or you would like to hear it again, subscribe to our podcast or ask your smart speaker to play Science Friday. Of course, you can email us the old-fashioned way, scifri@sciencefriday.com. Have a great weekend. We’ll see you next week. I’m Ira Flatow.

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